Dry bean cultivar characterisation by isoelectric focusing electrophoresis in polyacrylamide gel

A Spanish pinto bean local cultivar ‘Pinta’ was analysed by a standard electrophoretic technique, isoelectric focusing electrophoresis, in order to develop and test a reliable method of solving such food industry problems as fraud, adulteration and the identification and registration of different cultivars of legume seeds. The corresponding dry bean type protein extract was subjected to isoelectric focusing electrophoresis in polyacrylamide gel (IEF‐PAGE), and the resulting data were then studied with a suitable objective chemometric evaluation technique. Applying the Rasch model to the appropriate electrophoretic results, this Spanish dry bean type was clearly characterised by the order of the chemometric measures attributed by the model to each electrophoretic band in its proteinogram. The same chemometric technique was then applied to three more dry bean cultivars. They also showed their own characteristic order of the electrophoretic bands in their corresponding proteinograms. Consequently, this method could well be a valuable tool for legume seed identification and registration. The problems intrinsic to electrophoresis were solved with the Rasch model techniques. © 2001 Society of Chemical Industry.